Phase Transitions and Their Interaction with Dislocations in Silicon
In this paper, phase transformations (PTs) in silicon were investigated through molecular dynamics (MD) using Tersoff potential. In the first step, simulations of PTs in single crystal silicon under various stress-controlled loading were carried out. Results shows that all instability points under various stress states are described by criteria, which are linear in the space of normal stresses. There is a region in the stress space in which conditions for direct and reverse PTs coincide and a unique homogeneous phase transition (without nucleation) can be realized. Finally, phase transition in bi-crystalline silicon with a dislocation pileup along the grain boundary (GB) was carried out. Results showed that the phase transition pressure first decreases linearly with the number of dislocation pileups and then reaches a plateau with the accumulation of dislocations in the pileup. The maximum reduction of phase transition pressure is 30% compared to that for perfect single crystalline silicon.
KeywordsMolecular dynamics Phase transition criteria Homogeneous phase transition Triaxial loading Phase transition pressure Grain boundary Dislocation pileup
The support of NSF (DMR-1434613 and CMMI-1536925), ARO (W911NF-12-1-0340), and Iowa State University (Schafer 2050 Challenge Professorship) is gratefully acknowledged.
- 1.Blank, VD, Estrin, EI (2014) Phase transitions in solids under high pressure, Y Gogotsi, V Domnich (eds). CRC Press, New York Science and Engineering, Inst. of Physics, Bristol, Sect 3, pp 159–292Google Scholar
- 2.Levitas VI (2004) Continuum mechanical fundamentals of mechanochemistry. In: High pressure surfaceGoogle Scholar